[nicklecompte]

The whole idea of an annular solar eclipse is that the size is not actually exact :)

I think part of the perception that a total eclipse "perfectly" blocks the sun is that the corona has a fuzzy edge but the surface does not, so when the moon is actually larger than the sun in the sky you still see the same eerie coronal glow. In particular there's little perceptible difference between blocking 100% of the sun and blocking 105% of the sun, compared to 100% versus 95%.